FIG. 1. is a view illustrating the generation principle of electromagnetic waves.
As is generally known, when alternating voltage is applied to an antenna (for example, a dipole antenna), an electric field is generated and alternating current flows through the antenna, thereby generating a magnetic field. Here, when an electromagnetic field is separated from the antenna from a distance of d(λ(wavelength)2π), the electromagnetic field is changed into electromagnetic waves which propagate through space.
Here, a magnetic field area refers to the area from the antenna to a distance of λ/2π, and communication performed in such an area is referred to as magnetic field communication.
Unlike existing Radio Frequency Identification (RFID) technology and Ubiquitous Sensor Network (USN) technology, such magnetic field communication technology enables wireless communication to be performed around water, ground, and metal, and is a core technology which can overcome the limits of existing wireless communication technology.
Therefore, the present applicant achieved the present invention during the course of research into technology standards of magnetic field communication, which was being studied in order to increase national competitive power and preoccupy the world market through the national and/or international standardization associated with intellectual property related to magnetic field communication technology.